Relationship class to Survey123

Can relationships be created on existing feature services and keep the service live? Or can I create a relationship locally and overwrite the existing Survey123 feature service without causing problems for future survey submission?

Reason for this is that I want to create a relationship from my Survey123 feature service to a table of inspections details associated with each service request where work was performed.

With regards to the hosted layers, adding a relationship does require a republishing of the service. This can be done if you are working with a federated service in ArcGIS Enterprise, which has a different publishing approach working with an existing enterprise geodatabase.